A conventional screwdriver generally includes a handle and a shank which has a functional end. The functional end is used to engage with an object such as a bolt or nut, so that when rotating the screwdriver, the object can be loosened or tightened. However, sometimes the object is rusted and is securely attached to the parts that are adjacent to the object. In other words, the bolt and the parts adjacent to the bolt are a one-piece member, the rust grasps the bolt securely and the screwdriver cannot provide a large enough force to the bolt to let the bolt separate from the parts. The operator generally hits the rust or the bolt to vibrate and separate the rust from the bolt so as to easily rotate the bolt. Accordingly, the operator needs a hammer to hit the handle of the screwdriver to let the rust be broken.
The present invention intends to provide a screwdriver that has an impact device comprising a spring and an impact rod so that the user pushes the shank against the object and compresses the spring so as to let the impact rod impact the bit of the screwdriver to shake the rust and/or the bolt. The screwdriver of the present invention is easily used and provides an effective shaking feature to loosen a bolt or a nut that is secured to rust.